Internal Tibial Forces and Moments During Graded Running

Area of Science:

• Biomechanics
• Human Locomotion
• Sports Medicine

Background:

• Tibial stress arises from forces and moments acting on the bone.
• Understanding how running mechanics influence tibial loading is critical for injury prevention.

Purpose of the Study:

• To quantify the impact of different running grades on internal tibial forces and moments.
• To compare tibial loading during downhill, level, and uphill running.

Main Methods:

• Seventeen participants ran at a constant speed on an instrumented treadmill at various grades (0°, ±5°, ±10°).
• Motion capture data were collected and analyzed using an inverse dynamics-based static optimization approach.
• Internal tibial forces and moments were calculated at the distal third of the tibia.

Main Results:

• Downhill running (negative grades) resulted in significantly lower peak internal axial, anteroposterior, and mediolateral forces compared to level and moderate uphill running.
• Downhill running also led to significantly lower peak internal mediolateral, anteroposterior, and torsional moments across various comparisons.
• Uphill running at +10° showed reduced peak internal axial and mediolateral forces compared to level and +5° conditions.

Conclusions:

• Running on downhill gradients is associated with substantially lower tibial forces and moments.
• These findings indicate that downhill running may reduce overall tibial stress compared to level or uphill running.
• Grade adaptation is a key factor in modulating tibial loading during running.